Multiple endocrine neoplasia, type II (MEN II)

Familial acromegaly: case report and review of the literature

Familial acromegaly is an exceptional clinical entity when not associated with features of multiple endocrine neoplasia type 1 (MEN1). We report here 3 pedigrees in each of which 2 patients have been shown to develop acromegaly. In 4 patients, clinical follow-up, and biological screening allowed to confidently exclude MEN1. Absence of mutation in the MEN1 gene after direct DNA analysis in 2 pedigrees reinforces the conviction that the families do not have MEN1. In families 1 and 2, diagnosis was made at a very early age and voluminous adenomas with suprasellar expansion were already present at the time of diagnosis. We review the 20 previous reports of familial acromegaly, some of them questionable. Our 3 families, combined with some other published pedigrees, allow the delineation of a familial form of acromegaly, distinct from MEN1. Dominant inheritance with reduced, age-dependant penetrance is the most parsimonious model to explain the recurrences. Gs protein pathway could be the site of action of the gene responsible of familial acromegaly, but no data have been published to sustain or reject this hypothesis.

Importance of early diagnosis and follow-up in multiple endocrine neoplasia (MEN II B)

Three patients with a sporadic form of multiple endocrine neoplasia (MEN) IIb are presented. MEN IIb is the association of medullary carcinoma of the thyroid (MTC), pheochromocytoma and multiple mucosal neuromata. The age at diagnosis and primary therapy of MTC was relatively late (8, 16, 18 years) although thyroid enlargement (two cases), typical marfanoid habitus (two cases) or multiple mucosal neuromata (one case) had been evident since early childhood. The diagnosis was confirmed by measurements of tumour markers like calcitonin (CT) and carcinoembryonic antigen (CEA) for MTC, measurements of vanillylmandelic acid for pheochromocytoma, evaluation of the thyroid gland by sonography, scintigraphy and fine needle biopsy, and investigation of the adrenals by computer tomography and meta-(I-131) iodobenzylguanidine (I-131-MIBG) scintigraphy. After surgical treatment determinations of tumour markers confirmed relapses of MTC in all cases. Early diagnosis of MEN IIb, which could be made by recognition of the typical clinical appearance, is of special importance because of the poor prognosis of MTC.